A couple of the others ran to him. "Go on," he must have urged vehemently. "One of you is enough to stay with me. I'm going back to the submarine harbor. The rest--go on--report to me there."

As the rest ran toward us, there was nothing for us to do but to abandon the car ourselves and run for it. We left the road and struck into the trackless woods, followed closely now by two of the men who had outdistanced the rest. Through the woods we fled, taking advantage of such shelter as we could find.

"Look, here's a cave," cried Elaine, as we plunged, exhausted and about ready to drop, down into a ravine.

We hurried in and the bushes swung over the cave entrance. Inside we stopped short and gazed about. It was dark and gloomy. We looked back.

There was no hope there. They had been overtaking us. On down a pa.s.sageway, we went.

The two men who were pursuing us plunged down the ravine also. As ill-luck would have it, they saw the cave entrance and dashed in, then halted. Crouching in the shadow we could see their figures silhouetted in the dim light of the entrance of the cavern. One stopped at the entrance while the other advanced. He was a big fellow and powerfully built and the other fellow was equally burly. I made up my mind to fight to the last though I knew it was hopeless. It was dark. I could not even see the man advancing now.

Quickly Elaine reached into her pocket and drew out something.

"Here, Walter, take this," she cried. I seized the object. It was the searchlight gun.

Hastily I aimed it, the spot of light glowing brightly. Indeed, I doubt whether I could have shot very accurately otherwise. As the man approached cautiously down the pa.s.sageway the bright disc of light danced about until finally it fell full on his breast. I fired. The man fell forward instantly.

Again I fired, this time at the man in the cave entrance. He jumped back, dropping his gun which exploded harmlessly. His hand was wounded.

Quickly he drew back and disappeared among the trees.

We waited in tense silence, and then cautiously looked out of the mouth of the cave. No one seemed to be about.

"Come--let's make a dash for it," urged Elaine.

We ran out and hurried on down the ravine, apparently not followed.

Back among the trees, however, the man had picked up a rifle which he had hidden. While he was binding up his hand with a handkerchief, he saw us. Painfully he tried to aim his gun. But it was too heavy for his weakened arm and the pain was too great. He had to lower it. With a muttered imprecation, he followed us at a distance.

Evidently, to us, we had eluded the pursuers, for no one seemed now to be following, at least as far as we could determine. We kept on, however, until we came to the water's edge. There, down the bay, we could see Professor Arnold's yacht.

"Let us see Professor Arnold, anyhow," said Elaine, leading the way along the sh.o.r.e.

We came at last, without being molested, to a little dock. A sailor was standing beside it and moored to it was a swift motor-boat. Out at anchor was the yacht.

"You are Professor Arnold's man?" asked Elaine.

"Yes'm," he replied, remembering her.

"Is the Professor out on his boat?" we asked.

He nodded. "Did you want to see him?"

"Very much," answered Elaine.

"I'll take you out," he offered.

We jumped into the motor-boat, he started the engine and we planed out over the water.

Though we did not see him, the man whom I had wounded was still watching us from the sh.o.r.e, noting every move. He had followed us at a distance across the woods and fields and down along the sh.o.r.e to the dock, had seen us talking to Arnold's man, and get into the boat.

From the sh.o.r.e he continued to watch us skim across the bay and pull up alongside the yacht. As we climbed the ladder, he turned and hurried back the way he had come.

Elaine and I climbed aboard the yacht where we could see the Professor sitting in a wicker deck chair.

"Why, how do you do?" he welcomed us, adjusting his gla.s.ses so that his eyes seemed, if anything, more opaque than before.

I could not help thinking that, although he was glad to see us, there was a certain air of restraint about him.

Quickly Elaine related the story of finding the bomb in the rocks and the peculiar events and our escape which followed. Once, at the mention of the searchlight gun, Professor Arnold raised his hand and coughed back of it. I felt sure that it was to hide an involuntary expression of satisfaction and that it must be he who had sent the gun to Elaine.

He was listening attentively to her, while I stood by the rail, now and then looking out over the water. Far away I noted something moving over the surface, like a rod, followed by a thin wake of foam.

"Look!" I exclaimed, "What's that?"

Elaine turned to me, as Arnold seized his gla.s.ses.

"Why, it seems to be moving directly at us," exclaimed Elaine.

"By George, it's the periscope of a submarine," cried Arnold a moment later, lowering his gla.s.ses.

He did not hesitate an instant.

"Get the yacht under way," he ordered the captain, who immediately shouted his orders to the rest.

Quickly the engine started and we plowed ahead, that ominous looking periscope following.

In the submarine harbor to which he had been taken, Del Mar found that he had been pretty badly shaken up by the accident to his car. His clothes were torn and his face and body scratched. No bones were broken, however, though the shock had been great. Several of his men were endeavoring to fix him up in the little submarine office, but he was angry, very angry.

At such a juncture, a man in a dripping diving-suit entered and pulled off his helmet, after what had evidently been a hasty trip from the land through the entrance and up again into the harbor. As he approached, Del Mar saw that the man's hand was bound up.

"What's the matter?" demanded Del Mar. "How did you get that?"

"That fellow Jameson and the girl did it," he replied, telling what had happened in the cave. "Some one must have given them one of those new searchlight guns."

Del Mar, already ugly, was beside himself with rage now.

"Where are they?" he asked.

"I saw them go out to the yacht of that Professor Arnold."

"He's the fellow that gave her the gun," almost hissed Del Mar. "On the yacht, are they?"

An evil smile seemed to spread over his face. "Then we'll get them all, this time. Man the submarine--the Z99."

All left the office on the run, hurrying around the ledge and down into the open hatch of the submarine. Del Mar came along a moment later, giving orders sharply and quickly.

The hatch was closed and the vessel sealed. On all sides were electrical devices and machines to operate the craft and the torpedoes--an intricate system of things which it seemed as if no human mind could possibly understand.